1. P. T. Matthews:Phil. Mag.,41, 185 (1950).
2. J. Glimm andA. Jaffe:Quantum Field Theory Models (Les Houches Summer School, 1970) (New York, N. Y., 1970).
3. P. B. Burt:Phys. Rev. Lett.,32, 1080 (1974).
4. P. B. Burt:International Symposium on Mathematical Physics, University of Texas (Austin) Nov. 18–22, 1974 (Proceedings to be published).
5. H. Washini andT. Taniuti:Phys. Rev. Lett.,17, 961 (1966).